Question

What is an a.c generator or Dynamo used for? Name the principle on which it works.

Answer 1

A.C generator is used for the conversion of energy from mechanical state to electrical state and the current formed is alternating. The A.C generator works on the principle of Faraday’s law of electromagnetic induction.

Complete step by step solution:
A.C generator means alternating current generator, an a.c generator or Dynamo used for conversion of mechanical energy into electrical energy using the principle of Faraday’s law of electromagnetic induction.
Let us discuss the principle of Faraday’s law of electromagnetic induction.
The principle of Faraday’s law of electromagnetic induction states that, if a closed circuit is moved under the influence of the magnetic field of a permanent magnet then current will flow from the circuit.
Now, let us discuss the working of the A.C generator.
The magnetic fields will move from the North Pole to the South Pole and the coil will rotate as the shaft rotates, as the coil cuts the magnetic field and this develops EMF which causes the current to flow from the coil.
As per Fleming’s right-hand rule, the thumb represents the motion index finger represents the magnetic field and the middle finger represents the current and the following is the direction of current flows. As the current flows from the coil but every in every half cycle, the current changes the direction and this is how the A.C generator generates current or voltage.

Note:
Students should observe that the principle of Faraday’s law of electromagnetic induction tells that if a moving coil is under the influence of a magnetic field then current will flow from the coil and Fleming’s right-hand rule tells the direction in which the current will flow.